docs(schema): stop calling the graph contract 2.2.0

[rahlk]

V2SchemaCatalog.SCHEMA_VERSION is 2.0.0 and has been since this analyzer's unilateral drift to 2.1.0 / 2.2.0 / 3.0.0 was rolled back — but five comments still named 2.2.0 as if it were the current contract. Three stated it outright (V2SchemaCatalog, V2GraphProjector, V2Neo4jSchemaConformanceTest); two labelled the repository-artifact layer by the version it shipped under, which reads the same way to anyone who has not read the constant's own comment.

• The two class javadocs now point at SCHEMA_VERSION rather than restating a number that goes stale.
• The layer comments drop the version label.
• The history narration on the constant stays — it is the record of what drifted and why it was undone.
• Adds a line recording that Config-read literal tier: J_USES_CONFIG and J_READS_CONFIG_UNRESOLVED #232's config-read relationships and Entrypoint report on the application root, and per-framework attribution on the node #234's entrypoint properties ride the held baseline, and what that costs: detection is by presence, not by version, until Epic: scope every destructive Neo4j statement on the can:// id prefix; retire _module .github#50 re-baselines all three analyzers. With an explicit "do not bump this to advertise them".

No behaviour change. 546 tests green apart from CodeAnalyzerIntegrationTest, which cannot reach a Docker daemon here and fails identically on a clean main.